Art of producing lead salts by electrolysis.



E. D. GHAPLIN. ART 0I' PRODUGING LEAD SALTS BY ELECTROLYSIS.

APPLICATION FILED PEB. 3, 1906. 906,103. Patented De@.8,19os.

2 SHEETS-SHEET 1.

E. D. GHAPLIN. ART 0F PRODUCING LEAD SALTS BY ELEGTROLYSIS.

' APPLIOATIONHLED uns, 1906.

906,103. Patented Dec. 8, 1908.

2 SHEETS-SHEET 2.

A lowing is a speeiiication.

to the art of produc-y EDWIN DfenA-PLTN, OrBosToN, MASSACHUSETTS, AssreNoa To INTERNATIONAL LEAD'y eoMrANIns, A VOLUNTARY AssoorATioN.

ART OF P-RQDUCINGLEAD SALTS BY ELECTROLYSIS.

Specification o f LetterSlIatent. Application led FebruaryS, 1.906. Serial 110.299,239;

citizen of the United States, and a resident ofV Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in the Art of Producing Lead Salts by Electrolysis, of which the fol- My invention relates ing, pigments by electrolysis, and it relates more particularly to a process for so producing those pigments consisting of lead salts,

suehas lead carbonate, lead chromate, etc., from crude lead bullion or lead ore, carrying any impurity in any proportion, or carrying any` metals such as gold, silver, copper, etc.,

and recovering said metals.

, According to the present invention such crude bullion cast in the form of ingots, pigs, plates, and other convenient forms, is employed as the anode of an electrolyzer. con.- taining preferably an electrolyte which under the influence of the electric current will separate into a solvent of lead andan alkaline hydrate. By electrolytic action, a solution containing soluble salts of lead and such other metals as may be contained in the bullion or ore, and which are soluble in said solvent, is produced; by contact `deposition or by any suitable method, said other metals are recovered from said solution; and the remaining solution of a soluble salt" of lead is converted into the desired salt of lead. While any suitable method may be employed to prevent the formation in the electrolyzer of insoluble basic salts of lead, which is prejudicial to commercial working, l prefer in gen.y eral the method disclosed in Letters Patent No. 675,555 granted to Il. G.Halloran and myself, by which isA produced a solution of a soluble` acid salt of lead 3 and said solution may be converted into the desired lead salt,-

lead carbonate or lead chromateffin an suitable manner.

My invention may best be understood by .having reference to the drawings which accompany and form a part Of this specification, and which illustrate in diagrammatic .form several arrangements of apparatus and circuits whereby my process may be carried into efect; but it is to be understood that my invention is broader thanmere apparatus 4 and may be carried into ei'i'ect by a variety of ap aratus and circuit arrangements.

n the drawings, Figure 1 represents an ich lead carbonate may be produced directly carbonating a lead solution; Fig. is `fragmentary view of a modification of the apparatus shown in Fig. l, and represents apparatus whereby a lead solution maybe converted into lead ehromate; and represents an a paratus for carrying out'my process in 'whicfi lead carbonate may be prof? y apparatus for carrying out my process in? duced from a lead solution indirectly by precipitating lead hydrate therefromI the'n carbonating said hydrate.

ln the figures, 1 re resents a'supply tank` containing any suitab e electrolyte whiclrunE derthe action of the electric current will pro?n @est duce in the anode compartment of an electrolytic cell a solvent of lead and vsuch, other' 'metals as usually are present in crudeflead bullion or ore, and in the cathode comparti ment an alkaline hydrate. may contain an oxidizing agent or a solu le salt of such character as to prevent the formationof insoluble lead salts in the elec`` troly'zerQ. I f i Thile a great variety of solutions may be employed as electrolytes in the process herein c escribed', I prefer to employ an aqueous solution of a non-alkaline salt, such as a nil trate or an acetate of an alkaline base, for en?4 l ample, sodium nitrate, andas the salt to be mixed with said electrol Tte to prevent theformation of insoluble salts of lead, l' refer to em loy chlorid or chlorate of an al raline base, or example, sodium chlorid orsodiurn chlorate. Although the formation of inf soluble basic salts of lead may most effect-i ively be prevented by employing such 's'o'luble chlorid or chlorate salt and thereby ob-v taining a soluble acid salt of lead, l do not limit myself to this method but may em loy the method set forth in Letters Patents Tos. 555,232; 563,553, granted to A. B. Browne and myself, and 563,555," granted to AJB. Browne. il

Ishall hereinafter refer to the solution in tank l as the neutral solution and' shall assume that itcOntainssodium nitrate and sodium chlorid. f While any suitable form ofreell` or electrolyzer may be employed, I 'find anelectro# lyzer of the general type showriat 3 in iF-igs. 1 and 2, to be convenient for carrying out the herein described process. j vThe electrolyzer 1s divided into ananode compartment 3 and a cathode compartment The electrol te 3, by means of the foraminous diaphragme 4 4', between which is formed a compartment for receiving the electrolyte from the tank 1 through the pipe 2, which is provided with a valve 2 For the purpose of preventing a mixture ofthe anolyte and catholyte in the electrolyzer and consequently a precipitation of lead hydrate in the elec-trolyzer, I may maintain a preponderance of pressure on the inner sides of said diaphragme, refer ably by maintaining the level ot' the e ectrolyte between the diaphragme higher than the level of the anolyte and catholyte. The level of the electrolyte in the compartment between the dia hragms is indicated by the dotted line e, an the level of the anolyte and catholyte, which-is governediby the height of the bends of the outlet pipes 7 and 8, is indicated by the dotted lines In order to prevent said outlet ipes lrom siphoning the liquids out ofthe e ectrolyzer, the upper portion of each of said bends may be provided with an opening g to ec ualize the atmospheric pressure on the co umns of liquid in the twoportions of each of said pipes.

The crude bullion or lead ore may be placed in the anode compartment 3 and a cathode ol" cop er, lead or other suitable material, is placer in the cathode compartmentl The crude bullion' may be cast into in-' ots ies or other suitable forms and employed as the anodes, as shown in Fig. 2' at 5, 5; or, if'lead ore, which may be Wholly or partially smelted, or which may be untreated ore, is employed, it may be packed around a' plate or other member ol' carbon, pig lead, or lead bullion 5 as shown in Fig. 1 at 9. TWhile any suitable lead ore may be employed in the present process, galena will probably give the best results in the shape of by-products, for galena, which consists chiefly. of lead sulfid, is generally rich in silver and copper., and contains usually a certain quantity of gold, all of which metals may be recovered in a n'ietallic form as hereinafter more fully set `forth.

All'hen theelectrolyzer is charged with the .neutral solution Aandthe current froirr the dynamo D is passed therethrough by' the' conductors c4 andd, which are connected respectively tothe anodes 5, 5 and the cath ode (i, a mixed solution of soluble acid' salts ol` lead, silver, copper, etc.,'is l'orn'ied in the anode coinpartment 3', it, is assumed, galena is employed :is the ore to be treated; and an alkaline hydrate, whichin thepresent assumed case, is sodium hydrate, is formed in the cathode compartment 3". rl`he mixed solution in the anode compartment is drawn oil' by the pipe 8 and discharged intoA the tank 10 which contains metalliccopper shown in Fig, 1 asi copper bars, pigs or ingots 11,'and in. Fig. 2 as scrap copper 111', although copper in any suitable form may be employed, and by the reaction between said metallic copper and the soluble srver salt contained in said mixed solution', metallic silver is removed from said 'solution and deposited on the copper, while the soluble copper salt is added to said mixed solution. r[he mixed solution may beldrawnv oii from the tank 10 by the pipe 12,.and disf charged into a second. tank 13, containing metallic copper in any suitable form, herein shown as scrap copper 11', so as more thoroughly to remove the silver from the mixed solution. The solution may then be discharged rom tank 13 by the pipe 14, into the tank 15, containing metallic lead 16 in any suitable form. By the reaction between said metallic lead and the soluble copper salt contained in the solution, nietallic copper is removed from said solution and deposited on the lead while a soluble lead salt is added to the mixed solution.

While l have specifically' mentioned me# tallic copper as suitable for removing the silver from the solution by contact deposition, and metallic lead as suitable for so removin thecopper therefrom, it is to be understoo that I do not limitmyself to the employ,-

.ment of suchmetals inasmuch as vother metalsare suitable Jfor these purposes; nor do' l desire to be limited solely to the vmethod -of contact deposition for recovering the valuable metals from the mixed solution, or for removing objectionable ones therefrom, in-

asmuch asl consider any suitable method-to be within ,the scope et my invention. For example, if lead and sllver nitrate were formed by employing a nitrate salt as the` electrolyte, a zinc salt, such as-zi'nc chlorid might. be used which would precipitate the silver by double decomposition of itself and the silver nitrate, the precipitant becoming zinc nitrate and remaining 1n solution with theI lead nit-rate.

The. mixed solution mightl then be treated in a separat-e tank-with sodiuin hydrate in excess, thereby precipitat.-

fmoved or recovered, the solution, then containing only soluble salts of lead, may be converted into lead carbonate, 'lead chromate, or other desired leal sal-tin any suitable manner.

By way of example, in the process which may be carried out by the apparatus shown in Fig. 1, -the solution of a soluble salt, or salts of lead, may be drawn oli from tank 15' by the pipe 17, 'and discharged into the lower portion of the tank 18, containing the filter 18'. The filtrate may be discharged from the upper portion of said tank into the lower portion of the precipitating tank 20, Where it may be converted into lead carbonate by treatin it with a carbonate of an alkaline base. i desired, the tank 18 may be omitted and the solution discharged directly from tank into the precipitating tank, and in lieu of the particular form of precipitating tank shown anyother suitable type of precipitating tank may be employed. As indicated in Fig. la, the lead solution in tank 20 1.5v may be treated With a chromat'e or bi-chrov'- mate of an alkaline base, or with a mixture .of

the two, inorder'to precipitate lead chromate therefrom. 'In liig 13 the lead chromatef-is contained in the tank 40 and is discharged into the precipitating tank by the pi e 41, Whichis provi ed with the valve 41'.

the cathode compartment 3" is drawn ott by the vpipe `7 and dischar edinto the tank 26 l lead into lead car onate which may be rethrough a iilterpress, or otherwise prepared `foruser The filtrate which is substantially .the original neutral solution may be drawn from the tank 20, through the pipe 24, which enters said tank above' the lilter and conveyed to tank 1 by the ump 25. 'Steam coils 23. may be provided iJor tank 1 and, if necessary, .for tank 2O or otherv suitable means Imay be em loyed for maintaining` the 4 5 solutions at the c esired temperature. It is desirableto maintain lthe original neutral solutionat such temperature as to render soluble the lead chlorid which is formed inthe vearlier stages of the process if a soluble chlorid sait is employed in said solution, and it is desirable to maintain the lead solution in the precipitating tank at such temperature as yWill permit the precipitation therefrom 4of hydrated lead carbonate, if the soluble lead salt is to be converted into white lead.

While the direct process of making `White llead, above described, results in a product which for some purposes is preferred to that produced bthe indirect process of precipitating leadv ydrate from the soluble acid salt Vof lead, and then carbonating said lead hydrate, the latter process results ina roduct 'which has superior color-carrying an covering properties. An apparatus'.ivhereby such 6a indirect process may be carried out accord- 'IinFig l, the alkaline hydrate formed in J Wherefyit is `treated- Wit carbon-dioxid pro-Iv duced in the generator 28, `which is connected v with tankV 26 by thepi e' 29 provided with the soluble acidv salt ot moved in any suitable mannerfand run' ing to my present invention is' shown in Fig.

2, in which the reference characters have the same significance as in Fig. 1. According to the indirect process the alkaline hydrate formed in the cathode compartment 3' `is \70 discharged by pipe 7 into the tank-30, anda portion of said hydrate is conveyed by the pipe 31, provided with the valve 31' into the precipitating tank 32, and mixed With the ead solution which by thc pipe 19 is discharged in'to said tank i'rom the filtering tank 18. The lead hydrate formed in tank 32 may be discharged by pipe 34, provided with the valve 34' into the )recipitating tank 20, f While the iiltrate which is substantially the original neutral solution, may be pumped from the upper portion of the tank 32 to the supply tant 1. y The rest of the alkaline hydrate in the tank 30 is discharged into the tank 26, through the 85 pipe 30', provided with a valve 30" and con verted into. a 'bicarbonate oi' an alkaline base,-sodium bicarbonate Ain the present vassumed vcase,-by treatingit With carbondioxid from the generator 28. Said sodium bicarbonate is discharged by ipe 27, pro-l vided ivith the valve 27', into tlie precipitat-` ving tank 20, Where itronverts the lead hyand is discharged by the pipe 35.

lf gold or other metals W lich are insoluble by electrolytic action in the neutral solution employed are present in the bullion lorore, they will be thrown down in the anode com,- partment and may be recovered from the slimes in the bottom thereof.

Bythe process above described, lead orc which is practically valueless for smelting'l and reduction in the ordinary manner, may be proiitably employed for producing marl ketable lead salts; and any valuable metals I.that may be contained in such ore in quantities too small to pay for their recovery by ordinary methods, may be recovered as byproducts.

The proeessis continuous and in addition to the carbon-dioxid, or chromate solutions, employed, and the lead or'e consumed, rey 115 quires only the addition from time to time of fresh quantities of the neutral solution and the removal irom the anode compartment oi' the gangue or other insoluble matter.

It will be understood that I do not limit myself in the'present invention to any particular process ol' producing a lead or other pigment, or to any f particular apparatus whereby the hereindescribed process may be effected, inasmuch as I consider any such process Within the sco e of my invention and inasmuch as many di erent types of apparatus may be employed for carrying out my invention. f

f*- As applied to-the process herein, the Word V120 the solution.

continuous does not mean that at every vinstant there must necessarily be a lloW of The term as used hereln 1s satisfied if the solution is supplied as required tor use 111 the thtl'erent steps Without necessitatlng the lnterruptlon of the supply 1n one 'step by the performance .of a subsequent step. Thus, the supply of electrolyte to the electrolyzer might temporarily be shut otl and the solution in the electrolyzer drawn down to some extent, the supply of the elec trolyzer being again started and the eleetrolyzer replenished, this being Within the term leontinuously as applied to the supply ot electrolyte to the eleetrolyzer.

The i term is used to distinguish the present proci ess from those processes in w ance of one step by the performance ol a subsequent step.

,used herein. v

I cla-im:

trolyte to aneleetrolyzer containing lend ore or'bulhou as an anode, tornung by electroly- Sls'l'rom such leadpre or bulhou'a solution of a soluble salt ol lead', continuously withdrawing said solution troni the electa-elyZetl and recovering therefron m metalhe l'orm Isuch metals other tlntn'lead as may he in said solution, and trealing the resulting solution with a preeipit-atingV agent 'thereby eouveit` ing sait soluble salt of lead into the desired salt ol= lead. p

The )recess herein-described olI produc` ing white leadl'rom lead ore or bullion which consists in continuously supplying an eleetrolyte to an electrolyzer containing lead -ore or bullion as an anode, forming l'romsueh lead orc or bulliona solution ol a soluble salt,

of lle-ad, continuously withdrau'ingY said soln? tlvontlrom the eleetrolyzer and recovering:

therefrom in metallic l'orm sueh metals other than lead as may be 'u1 said solutxoluznnl treating-the resultingsolutiouu'ith a preeipitatiug agent `whereby the soluble saltol' lead is converted into lead carbonate. A

3. 'l`lte process herein described of producing lead salts l'roln lead ore or bullion which consists *in eontinuouslyl supplying au elec.n trolyte to au eleetrolyzer containing lead orc 'or bullionl as'au anode., forming by electroly;

sis l'roin such lead ore or bullion a solution ot' rich there is"l necessarily an interruption in the performsoluble Thus Where the solution Q producedin the electrolyzer by the electroli The i a soluble salt of lead in the presence of a soluble salt of such character as to prevent the formation of insoluble lead salts in the electrolyzer, continuously withdrawing said solution from the electrolyzcr and recovering therefrom in metallic form such metals other than lead as may be in `said solution, and treating the resulting solution With a precipitating agent whereby the soluble salt of lead is converted into the desired salt of lead.

4. 'l`hevproeess herein described of producing white lead from lead ore or bullion which consists iu continuously supplying an electrolyteI to an electrolyzer containing lead ore or bullion as an anode, forming by electrolysis from such ore or bullion a solution of a soluble s'ilt ot lead in the presence of an oXi- ,lixing agent to notent the formation of inlead sa ts in the elcctrolyzer, continuously uithdraning said solution and rcetnering therefrom in metallic torni such metals other than lead as may be in said solution, und treating the resulting solution with a precipitating agent thcrcby convertingr said soluble `salt ol lead into lead carbonate.

5. lhe process herein described of produringl lead salts from ore or bullion containing lead and other metals and recovering said other metals, uhieh consists in electrolytr tica-lly forming from sueh orc or bullion as an ,1. The process hert-1u deseribeil ol.' producl ing lead salts lro'm lead ore or'hullion, which -eonsists in continuously 'supplying` au elecanode .t solution containing soluble salts of lead and other metals, reeo.cr1ng by contact deposition said other 1uetals,'and comforting" said soluble salt ot lead into the desired salt of lead.

t3. The process herein described of producing lead salts tremore or bullion containino lead sil` er and copper and recotcring sai sil'er and copper, which consists in electrolyti allyl'orming l'rom suchoreorbullionas an snelneopper as. may be coutained'in the SOlu tion, and then passing thc'rema'ining solution into :u1otl1ery\esscl and therein converting the soluble lezul salt-.into the desired salt of lend. i 7. rlhe `prof-ess herein described of producing lead salts l'rom ore or bullion containin lead antljanother metals and recovering sai other metals, which consists in electrolyt-'- ically forming l'rom such ore o .r bullion as lan an'odc'a vsolution containing soluble saltsof lead and other metals, passing said solution successively through Avessels conttltining different metals, respectively, to reco' erin metallic lorm by contact deposition said other l metals and thenieonverting the soluble ksalt of `lead into the desired -salt of lead.

. to recover by contact deposition said other metal and then converting said soluble salt of"Y lead'into the desired salt of lead.

9. The process herein described of producing lead'salts from lead ore or bullion, which consists in continuously supplying an electrolyte to an electrolyzer containinor lead ore or bullion, formin by eleetrol sis lrom said ore or bullion a s o ution of a so uble acid salt of lead, continuously withdrawingsaid solution from the electrolyzer and recovering therefrom in metallic form such metals other than lead which may be in said solution, and

treating the resulting solution with a preci itating agent whereby said soluble acid sa t of lead is--converted-into another' salt of lead.

10. The recess herein described of rodueing'lea salts from leadv ore or bul ion,

which consists in continuously supplyin an electrolyte to an electrol zer contalning lead ore or ullion, forming y electrolysis from such' lead oreor bullion asolution of a soluble acid salt of lead, continuously withdrawing.

said solution from the electrolyzer andrecovering therefrom in metallic form such metal-s other than lead as may be in said so-l lution, and treating the resulting solution with a precipitatin agent thereby converting said soluble sa t of lead into lead carbonate. i

11. The )recess herein described of roducing lea' salts from lead ore or bul ion, which consists in continuously supplyin an electrolyte to an electrolyzer containing ead ore or bullion, forming by electrol sis from such lead ore or bullion a solution o a soluble acid salt' ol' lead in the presence of a soluble salt of such character as to revent the formation of insoluble lead sa ts in the electrolyzer, continuously withdrawing said solution from the electrolyzer'and recovering therefrom in metallic form such metals other than lead as may be in said solution, and treating the resulting solution with a prcei itating agent thereby converting said solu )le salt of lead into lead carbonate.

12. The process herein described of producing lead salts from ore or bullion con taining lead, silver and copper and recovering said silver and copper, which consists in electrolytically formino' from said ore or bullion a solution containmg soluble salts of lead, silver andV copper', passing said solution through a vessel containing metallic copper to recover in metallic form by contact deposi'- tion such silver as may be contained in the solution, passing the solution through another vessel containing)I metallic lead to re'- ally forming from such ore or bullion a solution containing soluble acid salts of lead and other metals, passin said solution successively through vesse s containing diierent metals, respectively, to recover in metallic form by contact deposition said other metals and then converting the said soluble acid salt oflead into lead carbonate.

14. The process herein described of producing lead salts from ore or bullion containing lead and another metal and recovering said other metal, which consists in electro-l lytically forming from said ore or bullion a solution containlng soluble acid salts of lead and said other metal, passing said solution through a vessel or vessels containing metal to recover by contact deposition said other vmetal and then converting said soluble salt of lead into lead carbonate.

15. The process herein described of producing lead salts from lead ore' or bullion by electrolysis, which consists in electrolytically forming from lead ore or bullion as an anode a solution of a soluble salt of lead, withdrawing said solution from the eleetrolyzer, recovering in metallic form such metals other than lead as may be in said solution, treating the resulting solution with a precipitating agent, thereby convertin said soluble salt of lead into the desired sa t of lead and regenerating the solution, and passing the regenerated solution into the electrolyzer.

16. The process herein described of producing white lead from lead ere or bullion by electrolysis, which consists in electrolytically forming from lead ore or bullion as an anode a solution ofasoluble salt of lead in the pres-- ence of an oxidizing agent to prevent the formation el insoluble lead saltsin the electrolyzer, recovering in metallic lorm suoli metals other than lead as may be in vsaid s0- then converting tlie soluble lead other 'metals, which consists in electro yticlution, treating the resulting solutionwith a preci itating agent thereby converting said soliib c salt of lead into lead carbonate and regenerating the solution, and passing the regenerated solution into therelectrolyzerl 17. 'lhe process herein described of producing lead salt from lead ore or vbullion byv electrolysis, which consists in electrolytically forming l'rom lead ore or bullion a. solutlon of a'soluble acid salt ol lead 1n the presence of soluble salt of such character as to prevent regenerating the solution, and passing the rethe formation of insoluble lead salts in the generated solution into the electrolyzer. 10 eleetrolyzer, withdrawing said solution from In testimony whereof, I have hereunto subthe electrolyzer, recovering in metallic form scribed my name this 5th (ley of Jan. 1906.

such metals other than lead as may be in said EDVIN D. CHAPLIN. solution, treating the resulting solution with( Witnesses: a xedptutin agent thereby converting said CHARLES C. KURTZ,

so uble salt o leadinto lead carbonate and GEO. K. WOODWORTH. 

